To further our understanding of the significance of changes in lung recoil with posture change, we have obtained lung conductance-lung volume data over the entire vital capacity range in awake and anesthetized dogs. We have measured "closing volume" (phase IV) and the phase III (alveolar introgen plateau) in anesthetized dogs in various postures. In the lateral posture the dog often does not have a phase IV in spite of a steep phase III. We found that stellate ganglion stimulation in anesthetized cats and dogs does not reduce lung compliance unless the animal is pretreated with isoproterenol. Preliminary studies in one baboon suggest this animal has a flow- volume curve more like man than does the dog.